I'm always scribbling down ideas with markers, when I'm working on Freedom Fall. I try to keep a stack of postcard-sized cards around with me all the time, which get filled up with level designs, lines of dialogue, to do lists and animation poses.
While I do most of my art in Photoshop these days, I still love to do rough marker sketches, as they're great for getting your ideas down on paper quickly.
More Freedom Fall art and info on the game project:
The male character reminds me of the main character from Secret of Mana.